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Displaying 726 - 750 of 871

Direct Observation of Coherent Population Trapping in a Superconducting Artificial Atom

April 20, 2010
Author(s)
David P. Pappas, Jeffrey S. Kline, Willim R. Kelley, Zachary Dutton, Thomas A. Ohki, john Schlafer, Bashkar Mookerji
The phenomenon of coherent population trapping (CPT) of an atom (or solid state artificial atom ), and the associated effect of electromagnetically induced transparency (EIT), are clear demonstrations of quantum interference due to coherence in multilevel

Ultra Sensitive NIR Spectrometer Based on Frequency Up-conversion Detector

April 7, 2010
Author(s)
Lijun Ma, Oliver T. Slattery, Xiao Tang
We developed a spectrometer for signals at single photon levels in the near infrared (NIR) region based on a tunable up-conversion detector. This detector uses a 5-cm periodically poled lithium niobate (PPLN) waveguide to convert NIR photons to a shorter

Niobium-silicide junction technology for superconducting digital electronics

April 1, 2010
Author(s)
David I. Olaya, Paul D. Dresselhaus, Samuel P. Benz
We present a technology based on Nb/NbxSi1-x/Nb junctions, with barriers near the metal-insulator transition, for applications in superconducting electronics (SCE) as an alternative to Nb/AlOx/Nb tunnel junctions. Josephson junctions with co-sputtered

Analysis of photoconductive gain as it applies to single-photon detection

March 30, 2010
Author(s)
Mary A. Rowe, G. M. Salley, E. J. Gansen, Shelley M. Etzel, Sae Woo Nam, Richard P. Mirin
We detail a mathematical framework for photoconductive gain applied to the detection of single photons. Because photoconductive gain is derived from the ability to measure current change for an extended period, its magnitude is reduced as detection speed

Toward scalable ion traps for quantum information processing

March 16, 2010
Author(s)
Jason Amini, Hermann Uys, Janus H. Wesenberg, Signe Seidelin, Joseph W. Britton, John J. Bollinger, Dietrich G. Leibfried, Christian Ospelkaus, Aaron Vandevender, David J. Wineland
The basic components for a quantum information processor using trapped ions have been demonstrated in a number of experiments. To perform complex algorithms that are not tractable with classical computers, these components need to be integrated and scaled

Enhancing Image Contrast Using Coherent States and Photon Number Resolving Detectors

March 15, 2010
Author(s)
Aaron Pearlman, Alexander E. Ling, Elizabeth A. Goldschmidt, Jingyun Fan, Christoph Wildfeuer, Alan L. Migdall
We experimentally map the transverse profile of diffraction-limited beams using photon number resolving detectors. We observe strong compression of diffracted beam profiles for high detected photon number. This effect leads to higher contrast than a

Grating-Enhanced Narrow-Band Spontaneous Parametric Down Conversion

March 10, 2010
Author(s)
Xiao Tang, Lijun Ma
We propose a new method to narrow the linewidth of entangled photons from spontaneous parametric down conversion incorporated with an internal Bragg grating. We study and show that it is a promising way to generate narrow-line entangled photons.

Low-loss superconducting resonant circuits using vacuum-gap -based microwave components

March 4, 2010
Author(s)
Katarina Cicak, Dale Li, Joshua Strong, Michael S. Allman, Fabio Altomare, Adam J. Sirois, Jed D. Whittaker, Raymond W. Simmonds
We have produced high quality resonant microwave circuits through developing a vacuum-gap technology for fabricating lumped-element capacitive and inductive components. We use micromachining to eliminate amorphous dielectric materials leaving vacuum in

Physics Laboratory: Activities, Accomplishments & Recognition 2008-2009

March 1, 2010
Author(s)
Jonathan E. Hardis
This report summarizes the research and measurement science carried out during 2008-2009 in the NIST Physics Laboratory. The Laboratory supports U.S. industry, government, and the scientific community by providing measurement services and research for

Frequency Comparison of Two High-Accuracy Al+ Optical Clocks

February 17, 2010
Author(s)
Chin-Wen Chou, David Hume, J.C. Koelemeij, David J. Wineland, Till P. Rosenband
We have constructed an optical clock with a fractional frequency inaccuracy of 8.6e-18, based on quantum logic spectroscopy of an Al+ ion. A simultaneously trapped Mg+ ion serves to sympathetically laser-cool the Al+ ion and detect its quantum state. The

Heralded, pure-state single-photon source based on a Potassium Titanyl Phosphate waveguide

February 15, 2010
Author(s)
Zachary H. Levine, Jingyun Fan, Jun Chen, Alexander E. Ling, Alan L. Migdall
WWe analyze the generation of single spatial mode, spectrally uncorrelated photon pairs via type II spontaneous parametric downconversion in a Potassium Titanyl Phosphate (KTP) waveguide using real experimental parameters. We show that this source can be

A superconducting nanowire single-photon detector system for single-photon source characterisation

February 1, 2010
Author(s)
C. R. Fitzpatrick, C. M. Natarajan, R. E. Warburton, G. S. Buller, Burm Baek, Sae Woo Nam, Shigehito Miki, Z. Wang, Masahide Sasaki, A. G. Sinclair, Robert Hadfield
Single-photon sources and detectors are key enabling technologies for photonics in quantum information science and technology (QIST). QIST applications place high-level demands on the performance of sources and detectors; it is therefore essential that

Quantum Computing

January 28, 2010
Author(s)
Emanuel H. Knill
Imagine a computer that can exploit quantum mechanics to solve previously intractable problems in physics, mathematics and cryptography. Such a quantum computer would revolutionize computing technology while teaching us about fundamental physics and ways

Fabrication of GaAs/AlOx micropillars for small mode volume

January 20, 2010
Author(s)
Richard P. Mirin
Micropillar devices have shown promise as single photon sources for applications in quantum key distribution as well as single photon metrology and fundamental science. For higher temperature operation (77K), a high quality (Q) factor cavity and a small

High-Order Coherences of Chaotic and Coherent Optical States

January 12, 2010
Author(s)
Martin J. Stevens, Burm Baek, Eric Dauler, Andrew J. Kerman, Richard J. Molnar, Scott A. Hamilton, Karl Berggren, Richard P. Mirin, Sae Woo Nam
We demonstrate a new approach to measuring high-order temporal coherences that uses a four-element superconducting nanowire single-photon detector. The four independent, interleaved single-photonsensitive elements parse a single spatial mode of an optical

Model of magnetic impurities within the Josephson junction of a phase qubita

December 23, 2009
Author(s)
David P. Pappas, R. P. Erickson
We consider a superconducting phase qubit consisting of a monocrystalline sapphire Josephson junction with symmetry axis perpendicular to the junction interfaces. Via the London gauge we present a theoretical model of Fe3+ magnetic impurities within the

Optimal filtering, record length, and count rate in transition-edge-sensor microcalorimeters

December 16, 2009
Author(s)
William B. Doriese, Gene C. Hilton, Kent D. Irwin, Francis J. Schima, Joel N. Ullom, Joseph S. Adams, Caroline A. Kilbourne
In typical algorithms for optimally filtering transition-edge-sensor-microcalorimeter pulses, the average value of a filtered pulse is set to zero. The achieved energy resolution of the detector then depends strongly on the chosen length of the pulse

Quantum information processing and quantum control with trapped atomic ions

December 14, 2009
Author(s)
David J. Wineland
The role of trapped atomic ions in the field of quantum information processing is briefly reviewed. We discuss some of the historical developments that enabled ions to enter the field and then summarize the basic mechanisms required for logic gates and the
Displaying 726 - 750 of 871